Arizona has passed a law cracking down on illegal immigrants -- the toughest of its kind in the US. It allows police officers to check the immigration status of anyone they stop or detain, if there’s a suspicion that the person is in America illegally. Driving it is frustration both at Arizona’s role as the main hub for illegal entry into America, and the organised cross border crime that’s come with it. Many support the law. But there is anger and fear among the Latino community: Legal citizens say they will be targeted by police just because of their skin. For Assignment Rob Walker travels to Arizona to explore why immigration has become such a hot political issue in the state.